Since the stock brakes are powerful enough to lock up the wheels, theoretically no upgrades are necessary for "casual" use - you'll get the same stopping distance because your tires are the limiting factor. The benefit of the Stoptech kit would be better initial "bite", and better heat dissipation, so repeated panic stops from 60 mph wouldn't cause fade as quickly.

I have installed the TRD kit on my FJ and I have to say it is not worth the money but they look nice. For about 1/3 of the price you can get a kit from Supreme Power that will give you about the same slotted and dimpled rotors. Another big improvement is changing your lines to SS. You can also upgrade the fluid to DOT 5.1 for the highest boiling point.